Joint Strike Fighter program. Refer to the Air & Space Power Journal (March-April 2014) study of the Joint Strike Fighter (JSF) global defense program, Exercise 11.22 (p. 641). The table below lists the year of initial operation and estimated annual cost (in millions of dollars) for 12 JSF military aircraft models. Find the rank correlation between cost and year of initial operation. Interpret this value, practically. Year Model Cost 1974 F-14 40 1975 F-15AB 28 1977 A-10 13 1978 FA-18AB 26 1978 F-15CD 30 1979 F-16AB 16 1981 F-16CD 20 1987 FA-18CD 29 1989 F-15E 31 1998 FA-18EF 55 2005 F-22 105 2012 F-35 80